- Researchers are interested in studying disorders that make individuals more susceptible to fungal infections, specifically infections with the Candida yeast. These disorders are often related to problems with the immune system and may have genetic factors, which suggests that researchers should study not only the individual with the disorder, but also his or her first- and second-degree relatives (such as parents, siblings, children, and first cousins). To provide material for future research, individuals with immune disorders and their first- and second-degree relatives will be asked to provide blood and other samples for testing and comparison with samples taken from healthy volunteers with no history of immune disorders.